3. Version Numbering Scheme for XFree86 4.0.x.

The version numbering format for XFree86 4.0.x releases is M.m.nx,
where M is the major version number (4), m is the
minor version number (0), n is the sub-minor version number,
and x is a letter. Full release versions up to and including
4.0.2 were 4.0, 4.0.1, and 4.0.2. Between-release snapshots are
indicated by including x, a lower case letter. For example,
the first post-4.0.1 snapshot was 4.0.1a. Release candidates have
been indicated by setting x to a one or two letter combination
with the first letter being "Z". For example, 4.0.1Z was the first
4.0.2 release candidate.

The next 4.0.x release will be an update release, not a full release.
These update releases will be indicated by incrementing the sub-minor
version number. So, the first post-4.0.2 update release will be 4.0.3.
Between-release snapshots will continue to be indicated with a lower
case letter, so the first pre-4.0.3 snapshot will be 4.0.2a.

The following example illustrates the release sequence from 4.0 through
to the post-4.0.2 update releases.